This invention relates to seed defiberizing processes and equipment intended for the purpose of treating seed with fibers adhering thereto. The invention particularly relates to the provision of effective abrasive surfaces for seed delinting and will be illustrated by use in cottonseed delinting equipment wherein defiberizing gin saws are conventionally mounted in spaced relationship on a rotating shaft. Such gin saws achieve mechanical separation of cottonseed and cotton fibers or linters by sawing the linter bearing cottonseed in a confined space. The gin saws require frequent, even daily, removal for sharpening with attendant dangerous handling and resetting of delinter clearances.
In contrast to delinters employing gin saw sets, the use of the presently disclosed abrasive seed defiberizing or delinting surfaces provides means for achieving surprising and unexpected advantages in machine capacity, lint and seed quality, electrical power usage and operator safety. Such advantages stem, in part, from the long lived, even full delinting season, qualities of the present open pattern abrasive particle cutting edges and to their non-glazing, non-burning properties.
Specifically, the invention comprises providing seed defiberizing surfaces which move in relation to fiber bearing seeds and abrade the fibers therefrom. The seed defiberizing surfaces comprise an open pattern of about 40 to about 80 abrasive particles per square inch of abrasive particles, preferably tungsten carbide grit, which abrasive particles are sized to U.S. Sieve Series numbers of about 12 to about 40. The abrasive particles are adhered, preferably by sinter metallic bonding, to the seed defiberizing surfaces.
The advantages of the presently disclosed abrasive surfaces are all the more surprising when viewed versus the prior art using various configurations of carborundum blocks in cottonseed delinting machines. For example, U.S. Pat. No. 358,256, issued to M. Crawford on Feb. 22, 1877, discloses a delinting machine having a vertically disposed, carborundum block faced conical stator with a conical wire brush surfaced rotor mounted concentrically therein. The cottonseed to be delinted was introduced at the top of the machine and proceeded downwardly in the annular passage formed by the conical stator and rotor while being acted upon by the carborundum surfaces and rotating brush. Other delinting machines using solid abrasive blocks mounted in various ways on vertical and horizontal shafts in delinting machines, with configurations designed to spread or regulate the passage of lint and seed through the machine are disclosed in such patents as U.S. Pat. No. 555,310 issued to J. J. Falkner on Feb. 25, 1896; U.S. Pat. No. 597,123, issued to John S. Rosamond on Jan. 11, 1898; U.S. Pat. No. 597,125, issued to F. E. Rosamond on Jan. 11, 1898; U.S. Pat. No. 614,435, issued to T. C. Black on Nov. 22, 1898; and U.S. Pat. No. 659,840, issued to W. C. Baxter on Oct. 16, 1900. Further patents wherein abrasive materials were used are U.S. Pat. No. 753,373, issued to R. Derdeyn on Mar. 1, 1904; U.S. Pat. No. 782,223, issued to R. Derdeyn on Feb. 14, 1905; U.S. Pat. No. 821,255, issued to W. A. Ragsdale on May 22, 1906; U.S. Pat. No. 936,282, issued to W. E. Worth on Oct. 5, 1909; U.S. Pat. No. 958,456, issued to W. E. Worth on May 17, 1910 and U.S. Pat. No. 973,159, issued to G. L. Blanchard on Oct. 18, 1910. Additional patents disclosing delinting machines are U.S. Pat. No. 1,019,955, issued to C. H. Golloher on Mar. 12, 1912; U.S. Pat. No. 1,032,938, issued to W. A. Pollock on July 16, 1912; and U.S. Pat. No. 2,724,148 issued to C. W. McMath on Nov. 22, 1955.
Despite the early use of shaped carborundum blocks in delinting machines, the use of such abrasive block materials in delinters was not continued, and carborundum block delinting was supplanted early in seed defiberizing practice by the use of gin saws. Applicants believe that this retirement from use of abrasive block material was due to such factors as the difficulty of shaping, fitting, balancing and retaining such frangible carborundum block materials in the rotational parts of a delinter. Apparently, there was also the further detrimental factor that the surfaces of such abrasive blocks tended to glaze over and burn the seed and fibers. It is also probable that such abrasive block materials had a considerable heat retention capacity so that they warmed to detrimental temperatures in extended delinting use.
As will be more fully set forth hereinbelow, the present improvement in delinting stems from the application of relatively open patterns of particular grit sizes of tungsten carbide and abrasive materials of similar hardness and cutting quality to seed defiberizing or delinting surfaces. The abrasive grit is preferably adhered to the delinting surfaces by means of sintered metallic or ceramet bonding. The abrasive grit can also be adhered by other means, for example epoxy adhesives, that will both provide the necessary mechanical bond and be sufficiently worn away in use to expose the cutting edges of the abrasive particles.